C(OP([CH2:9][C:10]([O:12][CH2:13][CH3:14])=[O:11])(OCC)=O)C.[H-].[Na+].[F:17][C:18]([F:32])([F:31])[C:19]([C:21]1[CH:26]=[CH:25][C:24]([F:27])=[C:23]([N+:28]([O-:30])=[O:29])[CH:22]=1)=O.O>C1COCC1.CN(C=O)C>[F:32][C:18]([F:17])([F:31])[C:19]([C:21]1[CH:26]=[CH:25][C:24]([F:27])=[C:23]([N+:28]([O-:30])=[O:29])[CH:22]=1)=[CH:9][C:10]([O:12][CH2:13][CH3:14])=[O:11]10.9 g (48.5 mmol) of ethyl diethylphosphonoacetate were slowly added dropwise to an ice-cooled suspension of 1.86 g (60% in mineral oil, 46.4 mmol) of sodium hydride in a mixture of 70 ml of THF and 20 ml of DMF. After the addition had ended, the mixture was stirred at 0° C. for another 30 min, and 10.0 g (42.2 mmol) of 2,2,2-trifluoro-1-(4-fluoro-3-nitrophenyl) ethanone were then added. The reaction mixture was stirred at RT overnight and then added to water. The mixture was extracted three times with ethyl acetate, and the combined organic phases were concentrated under reduced pressure. The crude product gave, after chromatography on silica gel (mobile phase cyclohexane/ethyl acetate 20:1 to 10:1), 9.23 g of the target product (71.2% of theory).
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